Estimating Principles 120203c

Question 1

1. Calculate the length of arc for each of the following; give your answers in the units shown and round to 2 decimal places ( used the π button on your calculator)
   a) a 145° when D = 1.25 m
   b) 110° when R = 2425 mm
   c) 60° when D= 61 inches
   d) 45° when R = 16.25’

Answer 1

a0 1.58m
b) 4655.67mm
c) 31.94 in
d) 12.76’

Question 2

2. Two square pads are to be welded onto the circumference of a 12-foot diameter tank.
   If the pads are to be 80° apart, calculate the centre to centre distance between pads.
   Give thean vr or caleulatot, tot. 2222222220ded 0 33)649 1181 3
   the i button on your calculator).

Answer 2

8’ 4.5”

Question 3

3. Four equally spaced platform clips spanning 90° are to be welded to the circumference of a 2250mm diameter tower. Give the centre to centre measurement
   between clips. Round off your answer to the nearest mm

Answer 3

589 mm

Question 4

4. A drawing gives the pitch of a sloped roof as 4:12 with a run of 5 metres. What are the vertical and slant lengths? Round your answer to two decimal places.

Answer 4

a) vertical length = 1.67 m
b) horizontal length = 5.27 m

Question 5

5. A circular oil storage tank ten feet in diameter has a roof slope of 2:12. If a one-inch overlap is provided all around, what is the dimension from the peak to the outside edge of the roof? Give your answer in inches to the nearest ⅓6”.

Answer 5

61’ 13/16”

Question 6

6. Three equally spaced intermediate vertical braces are required for each side of a roof truss that measures 24 feet from centre to edge and has a slope ratio of 5:12. What is the length of each intermediate vertical brace? Give your answer in feet and inches to the nearest 1/16”.
   a)
   b)
   c)

Answer 6

a) 26”
b) 5’ 0”
c) 7’ 6”

Question 7

7. A crane boom is being fabricated with the main girders and cross braces forming one metre squares on each side. Diagonal braces are required, running corner to corner.
   Find the length of the diagonal braces (cosine of 45° is 0.70711.) Give your answer in whole millimetres.

Answer 7

1414mm

Question 8

8. Trusses for a catwalk require bracing at 30° from vertical. The braces are to be welded to the columns three feet below the beams (tangent of 30° is 0.577 and the secant of 30° is 1.155.) Give your answers to the nearest ½6”.
   a) Find the distance from the column to the brace.
   b) Find the length of the brace.

Answer 8

a) distance of 1’ 8¾”
b) length of 3’ 5 9/16”

Question 9

9. A stair has a rise of 9 feet and a run of 15 feet. Use the Pythagorean Theorem to find the length of the stringers. Round your answer to the nearest inch.

Answer 9

17’6”

Question 10

Calculate the cost of the following using a standard unit cost of 30¢ per pound.
a) W6 x 15.0 x 20’
b) S4 x 9.5 x 10’
c) 4 sheets of steel plate 11 ga x 4’ x 12’ @ 5.1 lb per ft

Answer 10

a) $90.00
b) $28.50
c) $293.76

Question 11

11. Calculate the length of are for each of the following. Give answers in the units shown
    and round to two decimal places (Use n = 3.1416).
    a) 155° when D = 1.35 m
    b) b) 120° when R = 3725 mm
    c) 63° when D = 131 inches
    d) 45° when R = 22.25’

Answer 11

a) 1.83 m
b) 7801.64 mm
c) 72.02”
d) 17.48’

Question 12

12. A stairway has a rise of 8’ and a run of 9’. Determine the length of the slope using the Pythagorean Theorem. Express your answer in feet and inches to the nearest 16”.

Answer 12

12’ ½”

Question 13

13. Use the Pythagorean Theorem to determine the rise of a triangular-shaped object with a baseline of 156 mm and a slope of 287 mm. Express your answer to the nearest whole millimetre.

Answer 13

241 mm

Question 14

14. Use the Pythagorean Theorem to determine the baseline of a triangular-shaped object with a rise of 102” and a slope of 187”. Round your answer to the nearest 1/16”.

Answer 14

156¾”

Question 15

15. Calculate the length of the roof slope given the following information.
    Round answers to 2 decimal places.
    a) rise = 16’; run = 20’
    b) rise = 22’; run = 33’
    c) rise = 8 m; run = 14 m
    d) rise = 10 m; run = 13 m
    e) rise = 12 m; run = 20 m
    f) slope = ½; run = 32’
    g) slope = ½; rise = 5 m
    h) slope = ½; run = 18’

Answer 15

a) 25.61’
b) 39.66’
c) 16.12 m
d) 16.4 m
e) 23.32 m
f) rise = 4’; length = 32.25’
g) run = 30 m; length = 30.41 m
h) rise = 9’; length = 20.12’
i) run = 16 m; length = 16.49 m

Question 16

16. Fill in the blanks in Table 13.

Answer 16

Question 17

17. Calculate the length of the slope for each roof shown in Figure 23. Round your answers to two decimal places.
    a)
    b)
    c)

Answer 17

a) 12.37’
b) 12.65 cm
c 19.5’

Question 18

18. Use the trigonometry method to determine the amount of rise for an angle of 53° with a 526 mm baseline. Round your answer to the nearest whole millimetre.

Answer 18

698 mm

Question 19

19. Use the trigonometry method to determine the slope for an angle of 77° with a 106” baseline. Use the secant of the angle. Round your answer to the nearest 1/16”.

Answer 19

471 3/16”

Question 19

20. Determine the length of the structural steel pieces A and B on the roof truss shown in
    Figure 24. Round your answers to 2 decimal places.

Answer 19

a) A = 7.83 m
b) B = 3.91 m

Question 20

21. A spiral staircase turns 270° as it rises 10’ as shown in figure 25. The radius of the stairway is

Answer 20

17’ 3 3/4”

Question 21

What is the formula for arc length?

Answer 21

Question 22

What welding process does GTAW describe

Answer 22

Tig

Question 23

What is the technical term for Tig Welding ?

Answer 23

GTAW - Gas tungsten arc welding

Question 24

What welding process does this statement describe ? ______, is a process in which fusion welding is accomplished by the heat of an electric arc drawn between a non-consumable tungsten electrode and the work. a) GMAW b) GTAW c) PAW d) SMAW

Answer 24

b) GTAW

Question 25

What welding process was developed in the 40's to weld corrosion resistant metals such as Al & Mg. a) GMAW b) SMAW c) PAW d) GTAW

Answer 25

d) GTAW

Question 26

The GTAW arc can reach temps up to: a) 12 000°F b) 25 000°F c) 35 000°F d) 42 000°F

Answer 26

c) 35 000°F

Question 27

The ______ process is used especially where utmost weld quality is necessary; pressure vessels and high pressure piping systems.

Answer 27

GTAW

Question 28

The gas tungsten arc spot welding process permits automatic arc spot welding of __________ materials when you have access to only ________ side(s) of the joint. If necessary, you may automate this process to increase production. a) thick, one b) thick, all c) thin, one d) thin, all

Answer 28

c) thin, one

Question 29

What is the biggest advantage of spot welding?

Answer 29

minimal distortion

Question 30

Hot Wire GTAW: Resistance heating _______ the filler metal using a separate AC power supply. a) post heat b) pre heat c) energizes d) melts

Answer 30

b) pre heat

Question 31

Cold wire GTAW uses an automatic wire feed system. T or F

Answer 31

True. Cold wire GTAW is very similar to hot wire GTAW, except that the filler wire is not energized as it enters the weld zone. The wire enters the weld zone at ambient temperatures. The wire feeds to the puddle automatically.

Question 32

High amperage GTAW is often used to weld ________ in carbon steel pipe. a) cap pass b) root passes c) fill passes

Answer 32

b) root passes

Question 33

High amp GTAW often uses current settings more than a) 100 amps b) 200 amps c) 300 amps d) 400 amps

Answer 33

b) 200 amps

Question 34

High amp GTAW is capable of outperforming what welding process in similar circumstances. a) SMAW b) PAW c) SAW d) GMAW

Answer 34

d) GMAW - because it requires no tack preparation

Question 35

What welding process can join most weldable metals and alloys including Al, Mg, mild and low alloy steels, copper and nickel alloys?

Answer 35

GTAW

Question 36

What welding process is preferred for SS?

Answer 36

GTAW

Question 37

List the 6 main disadvantages of GTAW

Answer 37

1. Welding speed is slow 2. Deposition rates are slow 3. Excellent eye site and greater welding skills needed for manual GTAW 4. Particles from the tungsten electrode can break off and enter the weld pool,(tungsten inclusion) 5. indoor use only to maintain shielding gas 6. generally not used for very low melting metals such as tin, lead and zinc due to the intense heat created at the arc.

Question 38

What rays are emitted from a GTAW arc? a) ultraviolet b) visible light c) infrared d) both a & c

Answer 38

d) both ultraviolet and infrared rays are emitted from a GTAW arc

Question 39

bystanders to someone welding GTAW with argon on AL or SS should wear what shade? a) clear b) shade 2 c) shade 5 d) if a welding shield is up they dont require shades.

Answer 39

b) shade 2

Question 40

The most intense ultraviolet energy is produced when using what gas & metal combination?

Answer 40

Argon and AL or Argon and SS

Question 41

What 2 welding gasses displaces air causing an affixation hazard?

Answer 41

Argon & Helium

Question 42

When welding GTAW, atmospheric O2 reacts with the intense ultraviolet light what gas is created?

Answer 42

Ozone gas

Question 43

What 4 metals must you use extreme caution when welding due to the toxic fumes that are given off?

Answer 43

zinc, cadmium, lead & beryllium

Question 44

A _________ is used to supply light frequency current for arc starting on DC current and arc stabilization on AC current. a) high frequency current unit b) high amperage current unit c) frequency boosting unit d) amperage boosting unit

Answer 44

a) high frequency current unit